A data processing system (e.g., a desktop computer or a laptop computer) typically contains a number of components that consume power from a power supply (e.g., battery or AC adapter) to perform different tasks. For example, a microprocessor consumes power to perform computation, generating heat in the process; and, a cooling fan consumes power to dissipate heat.
Typically, a data processing system is designed for operating in a given environment to deliver high computation performance. One or more fans and heat sinks are typically used to cool the system so that the data processing system is not overheated in a condition of normal use.
To be energy efficient, some computers have power management systems which may temporarily put a hard drive or a display screen in a low power mode after idling for a period of time. When a component is in a low power mode, the component is not functioning at least in part (e.g., the display screen is not displaying images, a hard drive cannot be accessed for read or write operations, and a section of a chip is not energized with power to perform computation). In some systems, a cooling fan is triggered by a temperature sensor such that the cooling fan is turned on when the sensor detects that the temperature is above a threshold.
To protect from overheating, some microprocessors have built-in hardware to slow a processor when the processor is too hot. However, built-in hardware in a processor that slows down the processor when the processor is too hot is restricted to only changing processor performance to regulate the temperature. Intrinsically, it is not able to regulate other devices in the system or optimize thermal management of the entire system. Similarly, some computers (e.g., iBook laptops from Apple Computer, Inc.) automatically enter into a shut down when it is too hot (e.g., because a fan failed). Automatic shutdown of a notebook computer is an emergency solution for unusual situations, such as when the cooling fan is failing. It does not regulate the temperature during the normal use of the computer.
Thus, a computing platform (including a processor) is commonly designed for increased performance, which typically requires increased power consumption. However, computing platforms, especially in mobile applications, are also designed to reduce power consumption such that a limited power resource (e.g., a battery) can support the computing platform for an increased period of usage time.
These design goals are typically in conflict.
One conventional solution to the conflicting design goals is to provide a means for a user to switch the configuration of the computing platform between a high performance mode and a power conservation mode, as desired. For example, a computing platform may allow a user to select the desired mode via a hardware switch or via a menu and dialog box displayed by the computing platform. For example, some computers allow a user to manually select a clock frequency for the microprocessor.